Electric and hybrid electric vehicles are becoming increasingly popular. These vehicles include onboard energy storage systems (e.g., battery packs) that are recharged from a power source, such as a utility power source, by connecting (plugging in) the vehicle to an outlet. A vehicle's electric power supply system must support a plurality of vehicle functions that operate on electric energy. Such functions include normal vehicle operation devices and safety related devices such as window or mirror defoggers, anti-lock brake systems, traction or stability systems, lighting systems, etc. In addition to these devices, the vehicle's electric power supply system supports comfort, convenience, and entertainment devices. Some examples include air conditioning, heated seats, video/audio systems, and power outlet ports for user devices.
The increasing use of the electrical devices and accessories as described above directly affects the drain on the vehicle battery, and hence, the battery's useful life. The acceleration of battery aging has a direct correlation with the frequency of use of such devices, which uses the vehicle battery as a power source. Since the effective driving range of electric vehicles and hybrid electric vehicles depends upon the charge sustaining property of the vehicle battery (that is, the battery capacity), accurate and robust capacity estimation is needed for reliable and safe operation of electric and hybrid electric vehicles as well as for optimum power management systems for such vehicles.
A conventional method used to determine battery capacity is to use a time-consuming full discharging and re-charging process in a vehicle service center environment. Typically, this protracted process can take up to thirteen hours, during which time the vehicle owner is without use of the vehicle. Accordingly, it is desirable to provide a reliable and expedient battery charge capacity determination (or learning) process. Additionally, other desirable features and characteristics of the present invention will become apparent from the subsequent description taken in conjunction with the accompanying drawings and the foregoing technical field and background.